Embodiments of the present disclose relate to protecting structures from dynamic loading, and more specifically, to composite disc axial dampeners for buildings and structures.
When a structural member is excited by a horizontal external force, shear or similar horizontal movement may occur. Shear, especially in high building structures or towers may have serious impact on the conditions of the structure or even result in a collapse.
Dampeners play an important role in the protection of structures, e.g., houses or similar building structures, and they exist in numerous variants. Dampeners may dampen the motion by means of a frictional force between two moving parts attached between structural members of the building or by means of a fluid being forced to flow between two chambers through a restricted tube. Such dampeners act to dampen the seismic, explosion, and wind loading shear, and not an axial cross brace manner. Some dampers are actively changing the dampening effect corresponding to external conditions, and other dampers are passive dampers having a constant dampening characteristic.
An example of a passive dampener is the use of a Buckling Restrained Brace (BRB) which incorporates a metallic core or center axial member passing through an exterior buckling-constraining concrete cylinder. Such dampeners are heavy, costly to produce, and even more costly to assemble into a structural member of a building. In addition, the BRB dampener result in the metallic core experiencing plastic deformation and strain hardening resulting in permanent set and overall length change to due reacting the large compression and tension loads during a dampening event. The dampening event is a result of the horizontal movement that may occur, e.g., if the foundation of a building is displaced by an earthquake or by similar vibrations transmitted through the ground. Since the BRB dampeners are not self-righting, due to permanent set, the BRB dampeners must be replaced or repositioned to level the affected building or structure.
There is, therefore, a need in the art for an improved dampener that will handle these large compression and tension loads that are lighter weight, do not experience permanent set, are self-centering or self-righting after a dampening event, and have improved dynamic response due to the integration of composite materials. Accordingly, the present disclosure provides for storing the energy of the seismic, explosion, or wind event in the form of linear bending of the discs, instead of plastic deformation of the restrained core.